This invention relates to an image input apparatus, system, method and storage medium for inputting high-resolution and low-resolution images to a personal computer, for example. The invention further relates to an image sending/receiving system using a low-resolution/high-resolution image input apparatus.
FIG. 13 is an external view of a videoconference system according to the prior art. The system includes a host personal computer 101 having a display 102, and a video camera unit 103, which is capable of being controlled by the host personal computer 101, for inputting moving images to the host personal computer 101. The video camera unit 103 is mounted on a pan head 110. An integrated cable 104 connects the host personal computer 101 to the video camera unit 103. The host personal computer 101 has a keyboard 105, a mouse (pointing device) 106, a microphone set 107 and a communications cable 108.
FIG. 14 is a block diagram showing the flow of various signal in the system of FIG. 13.
Shown in FIG. 14 are the video camera unit 103 and pan head 110. An expansion board 111 for the host personal computer 101 is connected to a PCI bus of the host personal computer 101.
The video camera unit 103 comprises a lens unit 112, a lens-unit driver 113, an image sensing device (e.g., a CCD) 114, a correlated double sampling circuit 115, an automatic gain control circuit 116, an adder 117, a timing generator 118, a processing circuit [referred to as a VIDS (Vertical Interval Data Signal)] 119 for sending and receiving data in a video vertical blanking interval, a microprocessor 120, a microphone 121 and a microphone amplifier 122.
The expansion board 111 of the host personal computer 101 comprises an A/D converter 123, a camera process circuit 124, a video process circuit 125, a multiplexer/demultiplexer 126 for multiplexing and demultiplexing data, audio and images, a PCI bus controller 127, a processing circuit (VIDS) 128 for sending and receiving data in a video vertical blanking interval, a synchronizing signal generator (SSG) 129, a microprocessor 130, an audio A/D converter 131, an audio D/A converter 132, and an audio process circuit 133.
A CPU 134 constitutes a host computer system including a chip set and a memory, etc., and has a hard disk (HDD) 135 connected thereto via an IDE interface. Applications for image input and videoconferencing have been installed on the hard disk 135. A communications board 136 is connected to the host computer system.
The general operation of the system constructed as set forth above will now be described.
First, power is introduced to the host personal computer 101 and the videoconferencing application is started up. When the start of videoconferencing is designated by the videoconference application, the CPU (not shown) of the host personal computer 101 sends a prescribed command to the microprocessor 130 of the expansion board 111 so as to turn on the power supply of the video camera unit 103. In response to an indication from the microprocessor 130 that has received the above-mentioned command in this system, the power supply circuit of the expansion board 111 supplies power to the video camera unit 103 via the integrated cable 104. (The power supply circuit and power line are not shown.)
The video camera unit 103 thus supplied with power is thenceforth initialized and performs an image sensing operation by processing the command from the microprocessor 130 of the expansion board 111 by the microprocessor 120 of the video camera unit 103 via the VIDS 128, integrated cable 104 and VIDS 119. The components of the video camera unit 103 are controlled by commands from the microprocessor 120. A command in response to various commands from the expansion board 111 is output by the microprocessor 120, superimposed by the adder 117 upon the vertical blanking interval of a CCD signal adjusted by the correlated double sampling circuit 115 and automatic gain control circuit 116 and sent to the expansion board 111 via the integrated cable 104. A signal indicating the vertical blanking interval is generated by the SSG 129 on the side of the expansion board and is received by the VIDS 119 on the side of the video camera unit 103.
The CCD signal resulting from imaging by the video camera unit 103 undergoes correlated double sampling and gain adjustment. The above-mentioned CCD signal is superimposed upon the command by the VIDS 119 in its vertical blanking interval and sent to the expansion board 111 via the integrated cable 104. The expansion board 111 receives the CCD signal and converts the signal to digital data using the A/D converter 123.
The image portion of the digital data resulting from the conversion is supplied to the camera process circuit 124, which serves as signal processing means, and the command portion from the video camera unit 103 is supplied to the microprocessor 130 via the VIDS 128.
The camera process circuit 124 applies prescribed color processing and white-balance adjustment to the image signal from the video camera unit 103 in digital fashion and outputs Y and U/V signals, which are digital video signals that have been adjusted to a proper level. The camera process circuit 124 extracts a sharpness signal necessary to drive the lens unit 112 and outputs the sharpness signal to the microprocessor 130. A signal for driving the lens unit 112 is output from the microprocessor 130 to the video camera unit 103 via the VIDS 128 and 119. The digital Y, U/V signals are supplied to the video process circuit 125, which serves as image processing means, for being subjected to image-data compression processing and the like for purposes of communication. Here the communication compression scheme used is that for compressing moving images in videoconferencing. The scheme is typified by H261 of ITU-T, by way of example.
Besides being subjected to the above-mentioned compression processing, the digital Y, U/V signals are supplied to the PCI bus controller 127 for transfer to the host computer system 134.
The input from the microphone 121 of the video camera unit 103 is amplified by the amplifier 122, after which the amplified signal is input to the adder 137 of the expansion board 111 via the integrated cable 104 The input from the microphone of the microphone set 107 is amplified by an amplifier 138 of the expansion board 111 and then input to the adder 137. The adder 137 adds the microphone input from the video camera unit 103 and the microphone input from the microphone set 107 and inputs the sum to the audio A/D converter 131. The microphone inputs that have been converted to digital data by the audio A/D converter 131 are subjected to prescribed voice-data compression processing by the audio process circuit 133. Here the voice-data compression scheme used is that for compressing voice in videoconferencing. The scheme is typified by G728 of ITU-T, by way of example.
The above-mentioned compressed voice data and compressed image data are multiplexed together with the control command from the microprocessor 130 by means of the multiplexer/demultiplexer 126. The multiplexing scheme is that typified by H221 of ITU-T. The multiplexed data is transmitted to the communications board of another party via the communications board 136 and an ISDN line by control executed by the CPU of the host computer system 134.
The compressed multiplexed data received from the ISDN line is demultiplexed into an image, voice and a control signal by the multiplexer/demultiplexer 126. The demultiplexed compressed image signal is transmitted to the video process circuit 125, decompressed and then transmitted from the PCI bus controller 127 to the host computer system 134 via the PCI bus. The demultiplexed compressed voice data is decompressed by the audio process circuit 133 and then transmitted to the host computer system 134 via the PCI bus controller 127 so that audio can be heard from a speaker (not shown) connected to the host computer system 134. The decompressed voice data is also directed through the audio D/A converter 132 so that it can be heard using a speaker (not shown) and the microphone set 107 connected to the expansion board 111.
In the system described above, the user starts up the application that has been installed in the host personal computer 101 and controls the video camera, whereby it is possible not only to display the user's own image locally on the monitor 102 of the host personal computer 101 but also to communicate video, audio and data via the ISDN line. Further, since the system is capable of data communication, it is possible to use the mouse 106 and keyboard 105 to control not only the local camera but also the camera on the side of the communicating party by virtue of the application software.
In the system according to the prior art set forth above, a board including the circuitry up to the camera process circuit is inserted into a slot of the host personal computer 101 and thus can be received within the main body of the host personal computer 101. This makes it possible to achieve a reduction in the size of the apparatus. However, a disadvantage is that a special integrated cable must be used. Furthermore, the user must perform an operation such as removing the cover from the main body of the host personal computer 101 in order to install the expansion board. This is a troublesome and time-consuming operation.
Accordingly, a user-friendly system for inputting images to the host personal computer 101 has been developed and utilizes a standard interface with which the host personal computer 101 is equipped. In particular, one product (DVC 300, manufactured by Eastman Kodak, Co.) that is available inputs an image to the host personal computer 101 using a USB (Universal Serial Bus), which is an interface adopted in the specifications of PC 97 disclosed in the “PC 97 Hardware Design Guide” of Microsoft Corporation, and makes it possible to view an image on the monitor of the host personal computer 101 merely by using a driver application without relying upon a special-purpose board.
However, the two systems described above merely transmit a digital video signal (moving images) to the host personal computer 101 via an interface cable. In a case where a still image is to be displayed, the image in a display memory within the host personal computer 101 is merely frozen on the monitor screen. In other words, with the systems described above, the image input to the host personal computer 101 is only a digital video signal (a moving image). Even if an event such as loss of an image due to a data error should occur, therefore, the effect upon the moving image is small because the image is refreshed in successive fashion. Accordingly, a drawback is that these systems do not take into account the handling of digital still images when they are transferred to the host personal computer 101.